Premix adhesive unsuitable for fire hearth tile

[JPapiPE]

I was advised by a fire tech engineer on this site via direct communication that premix tile adhesives were Ok for hearth tile applications. Even the kind with petroleum distillates. So being lazy I figured why not and did buy 2 containers of the stuff from Home Depot at about $20 including tax /gallon. There was a little something in the back of my head that kept saying no, this isn't right. So i dug a little deeper and found Michael Byrne's book on
"Setting Ceramic Tile" On one the back shelves of my library. He distinctly spells out that no premix adhesive is appropriate for fire heath tile setting. He is a 30 year expert in this field and has written several books under the distinqueshed publisher, Taunton Press. So I guess I will use thinset. He and others claim it is stronger and more flexible ...plus fireproof... which is what we all should be after. No offense to the person that advised me wrongly, he is a good and decent man and this was just one of the times his advice fell through the cracks.

So I guess the motto of this story is that we all are responsible for our own stove installations. So we should do the best we can and if something seems wrong it probably is.
Many thanks to this forum, I have learned so much for which i am grateful, Joe

 

[PeteD]

If you were to spend some time on the John Bridge forum (tile - an excellent forum), you would never use pre-mixed. It's not fun, but buy the powder.

Pete

 

[begreen]

If I remember right, the comments here were against the premix.

https://www.hearth.com/talk/threads/19720/

 

[DiscoInferno]

I used premix from Home Depot to glue up 2" slate tiles, and after several days I noticed it was still pliable. Only then did I find the bit in the fine print on the back about not using for fireplaces. The stuff I got will actually melt/burn in direct flame. Sort of irrelevant for me: it's a ZC fireplace, so I "legally" had paper-backed drywall behind the tile anyway and my surround never gets more than warm in any case. I did mix up the right stuff for the grouting.

 

[Noah]

If you were to spend some time on the John Bridge forum (tile - an excellent forum), you would never use pre-mixed. It's not fun, but buy the powder.

Pete

I agree, I searched that forum a lot in the last few weeks to build my hearth and everyone recommends that you not use pre mix thin-set. I guess the pre-mix is an adhesive while the powder mix is actually a cement and bonds better.

It's not that hard to mix the powder and I am glad I used it. It's cheaper too I think.

 

[Andy99]

I'm in the tile business and I'm very familiar all the setting materials you are talking about. You should not use mastic(premixed). I would only use a Latex Modified Thinset for the best tile installation. Its a little more expensive then traditional thinset but the benefits out way the cost. You get better adhesion and more tolerance of movement of the underlayment from either flex or expansion and contraction.

 

[Hogwildz]

Ive read both sides of this debate a few times.
I used a pre mix, not sure exactly what it contained at this point in time.
Hearth is holding well, and still looks great.

 

[Tfin]

Ive read both sides of this debate a few times.
I used a pre mix, not sure exactly what it contained at this point in time.
Hearth is holding well, and still looks great.

Same here, and same here FWIW.

 

[webbie]

Obviously, this depends on the heat radiation (down) of the particular stove. In most cases - where the hearth almost never gets too hot to hold your hand on - just about any adhesive will do. However, for those who want to go the extra mile....use either powder thinset or certain epoxies which are actually rated for a higher temp. As I remember from one old thread, some are rated up to 300 degree plus....that should be high enough for any normal stove with legs or a pedestal.